Field of the Invention
The present invention relates to a technique to perform display control in accordance with a power state for a display unit included in an image forming apparatus or the like.
Description of the Related Art
It is common for an electronic apparatus (hereinafter, simply called an “apparatus”), such as an image forming apparatus, to include a display unit consisting of an LCD or the like for a user to operate or for displaying various kinds of information. Then, in recent years, high power-saving performance is required and the apparatus is designed so as to immediately make a transition into a power-saving mode in the case where the apparatus is not used for a predetermined period of time. In this power-saving mode, supply of power to each main unit within the apparatus is suspended, and therefore, commonly, the display unit also turns off and is in the state where it cannot be used. In the case where the apparatus is in the power-saving mode, a user returns the apparatus from the power-saving mode by pressing down a power-saving button or the like. At this time, a control unit in charge of controlling the whole of the apparatus generates and outputs a UI screen to be displayed on the display unit, but it takes a certain time until the UI screen is displayed on the display unit. The reason is that the control unit performs initialization processing (startup processing) of the apparatus before starting to generate and output the UI screen. In the case where the turned-off state of the display unit continues despite that a user has operated the power-saving button or the like, the user who desires to use the apparatus will feel anxiety because of not knowing whether returning from the power-saving mode is in progress normally. Consequently, it is important to display the UI screen earlier to eliminate the user's anxiety such as this.
Regarding this point, a technique to produce a temporary display on a display unit during the period of time from when instructions to return from the power-saving mode are given by a user until a control unit starts up and starts outputting a UI screen has been proposed (Japanese Patent Laid-Open No. 2009-66886). In the technique, a sub display controller capable of operating also in the power-saving mode is provided separately from a main display controller. Then, the sub display controller produces a display of “Wait a while” during the period of time from when instructions to return from the power-saving mode are given until the main display controller generates a regular UI screen. Then, at the point in time of generation of the regular UI screen by the main display controller, the display is switched to the regular UI screen. In this case, the sub display controller acquires the data of the temporary display screen from a memory (ROM) and produces a display.
Among image forming apparatuses or the like, there exist some equipped with the function to display a UI screen customized by a user in place of a fixed predetermined UI screen. The customization function is a function that enables a user to arbitrarily change and set the item to be displayed on the UI screen, the character size, the color, etc., so that usability is improved. In the apparatus equipped with the customization function such as this, it is desirable to reflect the customized contents also on the temporary screen that is displayed at the time of return from the power-saving mode. The reason is that in the case where the temporary screen that is displayed immediately after the return from the power-saving mode differs from the regular customized UI screen that is displayed after this, a user is caused to have a feeling of difference. However, according to the technique in the above-described Japanese Patent Laid-Open No. 2009-66886, the display screen prepared in advance and stored in the ROM is just displayed. The timing to customize the UI screen can be arbitrary and the contents thereof can be different for each user, and therefore, it is difficult to prepare in advance the display screen corresponding to the customized UI screen each time.